The present invention is directed to a bead breaker for breaking the tire bead between a tire and a rim or wheel.
The tire bead is the inner edge of the tire that contacts the wheel flange and presses against the bead seat. The bead seals against air loss in tubeless tires and grips the wheel rim for transmitting various loads such as steering, traction, and braking. Tire bead failure can cause loss of air pressure in the tire as well as detachment of the tire from the wheel or rim.
The tire bead is a structure composed of high tensile strength steel wire formed into hoops that function as anchors for the tire plies (layers) that hold the tire assembly onto the rim of the wheel. Most tire beads consist of steel (piano-type) wires in parallel in a continuous rubber tape or ribbon, which loosely secures the wires in a soft insulating rubber. The ribbon is wound into a hoop, commonly made of five courses. The end result is a grommet composed of a bundle or stack of wires.
In order to remove a tire from a wheel, the tire bead must be “broken.”
Currently all truck tires beads are broken down by hammer and wedge. This task is accomplished by first releasing the air from the tire, then laying the wheel and tire on the ground. The mechanic takes his hammer and wedge and proceeds to strike the tire where it is attached to the wheel (the bead). The mechanic continues to strike at this point until the bead separates from the wheel. The mechanic lifts the wheel and tire, spins it around and lays it down with the opposite side up and begins to repeat the operation until this bead is broken. With this being accomplished, the mechanic can start removing the tire from the wheel.
Several attempts have been made to create a tire bead breaker, but to date they all present one or more difficulties including but not limited to being labor intensive, being relatively dangerous to operate, requiring heavy lifting, being environmentally unsafe, being time consuming, and not being truly portable/mobile.
One example of an attempt to create a tire bead breaker is U.S. Pat. No. 4,102,380 to Holder (the “Holder reference”). The Holder reference discloses a tire bead breaker machine having a frame that includes a pair of upstanding frame members interconnected by a pair of telescopic members. A hydraulic power cylinder moves the upstanding members towards and away from each other by expanding and contracting the telescopic members. In other words, the Holder device expands (opens) and contracts (closes). The expanding and contracting movement of the upstanding frame members requires a significant amount of power that is provided by the hydraulic cylinder. A bead breaker arm includes a pair of hooks on one end, the bottom of which pivotally engages a pin on one of the upstanding members while the other hook movably engages another pin spaced above the first pin to allow the arm to move vertically within limits, the limits being defined by the hook and the opposite end of a curved surface along which the second pin engages as the arm is raised and lowered. The outer free-end of the arm includes a pivotal wedge member having an upwardly curved tapered end for engaging the rim and moving between the tire bead and the rim. The other upstanding frame member includes a rim holder for limiting the rim against vertical movement. A tire support cradle is formed from a plurality of arcuately arranged roller rods connected to one of the upstanding frame members, telescopically and rotatably engaging the other frame member to allow for rotation of the tire and inward and outward movement of the outer upstanding frame member relative to the inner upstanding frame member. To break the tire bead, the hydraulic cylinder contracts to move the upstanding frame members closer together. This forces the tapered end of the wedge between the tire sidewall and the wheel rim to break the tire bead. One problem with the Holder device is that its components (e.g. the upstanding frame members, pair of telescopic members, and the hydraulic cylinder) are heavy and not very maneuverable. Further, the use of the hydraulic cylinder is not environmentally safe.
Another example of an attempt to create a tire bead breaker is U.S. Pat. No. 6,305,453 to Zielewicz (the “Zielewicz reference”). The Zielewicz reference discloses a tire bead breaking apparatus that includes a vertically oriented frame disposed upon a wheeled base. A hydraulically actuated ram is pivotally mounted to the frame. A bead breaking shoe is attached to a distal end of the ram, and engages the beaded edge of a tire mounted upon a swivel pan rotatably mounted to the base. The bead breaking operator is able to simultaneously operate the ram, while rotating the tire disposed upon the swivel pan. The Zielewicz device is designed to work with a tire that lies flat (horizontal) and centered on the swivel pan. This horizontal (flat) positioning of the tire requires significant strength for manipulating heavy tires, both in lowering the tire to a flat orientation and in lifting the tire to a vertical position after the work is complete. Further, the use of the hydraulic cylinder is not environmentally safe.
Yet another example of an attempt to create a tire bead breaker is U.S. Pat. No. 4,953,606 to Brown (the “Brown reference”). The Brown reference discloses a tire bead breaker having a jack stanchion adapted for substantially vertical use, a jack body mounted on the stanchion for substantially vertical movement therealong, a wheel support associated with and movable with the body and extending outwardly substantially horizontally therefrom, the support having a substantially planar bed for supporting a wheel in substantially horizontal posture with a portion of the tire tread juxtaposed with the stanchion such that the side wall thereof faces substantially upwardly, and a butting device affixed to the stanchion above the support and being adapted to engage a tire sidewall adjacent to the tire rim in order to break the tire bead from the rim in response to upward movement of the body and support and a wheel supported thereon. As with the Zielewicz device, the Brown device is designed to work with a tire that lies flat (horizontal). This horizontal (flat) positioning of the tire requires significant strength for manipulating heavy tires, both in lowering the tire to a flat orientation and in lifting the tire to a vertical position after the work is complete.